Experts criticize government's threat sharing, noting it wants the private sector to be generous but it's stingy with the private sector

The nation's critical infrastructure is vulnerable to cyber attacks and better information sharing is needed to strengthen defenses.

That's the message Charles Edwards, deputy inspector general for the U.S. Department of Homeland Security, told a Congressional committee at a public hearing on Thursday.

Since 1990, Industrial Control Systems (ICS), which are used to manage components of the country's critical infrastructure, have been connecting to the Internet to improve their operations, Edwards explained in written testimony submitted to the House Subcommittee on Cybersecurity, Infrastructure Protection and Security Technologies.

However, companies hooked their control systems into the public Internet with little regard for security. "[Security] for ICS was inherently weak because it allowed remote control of processes and exposed ICS to cyber security risks that could be exploited over the Internet," Edwards said.

"As a result, ICS are increasingly under attack by a variety of malicious sources," he continued. " These attacks range from hackers looking for attention and notoriety to sophisticated nation-states intent on damaging equipment and facilities, disgruntled employees, competitors, and even personnel who inadvertently bring malware into the workplace by inserting an infected flash drive into a computer."

Edwards cited survey results that showed that a majority of the companies in the energy sector had experienced cyber attacks, and about 55 percent of these attacks targeted control systems.

"Successful attacks on ICS can give malicious users direct control of operational systems," he said, "creating the potential for large-scale power outages or man-made environmental disasters and cause physical damage, loss of life, and other cascading effects that could disrupt services."

He went on to say that information sharing between government and the operators of control systems was important in strengthening the security of those systems.

Threat information sharing has been a sore point between the federal government and private sector for years. "The government classifies information that on review or second look needs to be classified," Shane Shook, chief knowledge officer and global vice president of consulting for Cylance, said in an interview.

"By classifying it," he said, "they restrict it so much that it's not available to the organizations and people it really matters to."

Information in cybersecurity is continuously evolving so even short delays in receiving information can be harmful. "You can't wait three weeks, six months -- whatever the period is for government review -- in order to have information that's useful," Shook said.

He acknowledged, though, that in the last two years the DHS has done a great job passing information the energy and financial sector. "The problem is the information is always six to nine months old," he said.